JP3995266B2

JP3995266B2 - NMR flow tube

Info

Publication number: JP3995266B2
Application number: JP53629797A
Authority: JP
Inventors: ハナー，ロナルド
Original assignee: Varian Inc
Current assignee: Varian Inc
Priority date: 1996-04-04
Filing date: 1997-04-02
Publication date: 2007-10-24
Anticipated expiration: 2017-04-02
Also published as: DE69734914D1; EP1574871A2; JPH11507441A; CA2222172A1; EP0830613B1; DE69734914T2; EP1574871A3; WO1997038325A1; EP0830613A1; US5867026A

Description

ＮＭＲ用の流管
発明の背景
本発明は一般的に化学分析の分野に関し，特に高性能液体クロマトグラフィ（ＨＰＬＣ）および核磁気共鳴スペクトロスコピー（ＮＭＲ）の分野に関し，とりわけこの二つの分析技術のオンライン結合を可能にする方法に関する。特に，本発明はＨＰＬＣの分離能力への悪影響を最小にして，ＮＭＲの高分解能，高感度かつ容易な使用を可能にするＮＭＲ検出セルに関する。
高性能液体クロマトグラフィ（ＨＰＬＣ）は有機混合物を分離するために広く使用されている。ＨＰＬＣとともに一般的に使用されている紫外線，屈折率および蛍光検出器は，ＨＰＬＣ溶離液の定性分析用のＮＭＲ，ならびに赤外線（ＩＲ）および質量分析計（ＭＳ）と同じように強力なものではない。赤外線および質量スペクトロスコピーは分離と強力な分光分析の両方を行うためにガスクロマトグラフィ（ＧＣ）とうまく結合するものの，ＨＰＬＣを好適な分光技術の一つに対して同様の結合を行う試みはうまくいかなかった。
徹底的な開発後，ＨＰＬＣと結合した質量スペクトロスコピーは商業的に入手可能となっている。ＨＰＣＬオンラインの紫外線スペクトロスコピーへの結合は溶媒の干渉のためまくいかなかった。ＮＭＲ（これは匹敵するものがないほどの構造上の情報をを与え，ＨＰＬＣにより合理的に整合するサンプル条件をもつ）は，ＨＰＬＣと結合する好適な分光方法にみえる。
これら二つの分析技術を結合する試みは基本的にＮＭＲ検出器の低感度のためにうまく行かなかった。1978年にオンライン結合ＨＰＬＣ-ＮＭＲの最初の装置の出現以来（LauWil86），ＮＭＲの感度の改良が，鉄製の磁石ではなく超伝導ソレノイドＮＭＲ磁石の使用により成し遂げられた。ＮＭＲの感度の増加をなすための他の手段は，過度の注入容量で過剰に充填される，予備的または準予備的スケールカラムまたは分析スケールカラムの使用による。
これら二つの代替手段には種々の欠点がある。これら方法のいずれにも関連するより高い注入容量は過度にバンドを広げる結果となる。バンドの広がりは，サンプルの前磁化条件を満たすために，カラムの後に大きなデッドスペースが必要となるとさらに増加する。これら二つの方法のさらなる欠点はカラム効率の急速な低下および適切に廃棄されなければならない多量の溶媒の発生を含む。
よりよいアプローチはＮＭＲ感度を改良し，容量の注入を微小な量に限定するできることである。ここで説明する本発明は，ＮＭＲの感度およびラインの形状を改良するとともに，クロマトグラフのバンドの広がりのレベルを低く，磁場の一様性のレベルを高く維持する方法を提供する。
発明の要約
本発明の一態様にしたがって，液体クロマトグラフィのサンプル用の検出セルが核磁気共鳴分光計において使用される。その検出セルは，円錐形にテーパーが付けられた出口ノズルをもつ入り口管，分析管，および円錐形にテーパーが付けられた入り口ノズルをもつ出口管を含む。三つの管は，同じＮＭＲ両立材料（好ましくは，高純度の石英，ホウケイ酸ガラス組成物およびサファイアのいずれか）から構成されている。分析管の内径は入り口管および出口管の内径よりも大きく，そのため小さいもの，大きいもの，小さいものの順となる形態をもつ。
入り口管の出口端部は分析管の入り口端部内に挿入され，出口管の入り口端部は分析管の出口端部内に挿入される。入り口および出口管は適切な方法で，挿入された端部から離れて分析管にシールされる。
発明の特徴は，（1）ＨＰＬＣシステムからＮＭＲへの適切な圧力許容結合のために必要な小さな寸法において高い機械的強度を可能にし，さらに（2）液体クロマトグラフの流体出力における影響を最小にするとともにＮＭＲ感度および分解能に必要な高度の構造的対称性を維持して，挿入シールを可能にする方法で，異なる内（直）径をもつ三つの管を組み合わせることである。
ＮＭＲ検出器のより高い感度は，信号対ノイズ（Ｓ/Ｎ）比を増加させることで得られる。入り口管および出口管に対する分析管の内径を増加させると，観測容積が増加するために信号強度が増加するとともに，ガラスの直径が減少してノイズが減少して，このことが達成される。観測容積は，過度にバンドの広がりを生じさせることになる注入容積の増加を必然的に伴う点までは増加しない。
大きな分析管の容積の主要な利点は，サンプルの濃度に対して，分子の数が検出器内で増加することから信号強度が増加することである。このことは，全体の設計に依存して，ノイズの低下をもたらすより小さな直径のコイルを可能にする。
説明する検出器セルは，連続した流れの下での分析でも，停止した流れの下での分析でも使用できる。
【図面の簡単な説明】
図１は連続流セル100におけるＮＭＲ検出セルの略示図である。
図２はここで説明する組み立てられた検出流セルを示す。
図３は組み立てられる前の検出流セルの三つの個別片を示す。
図４乃至７は説明する種々の検出流セルを示す。
図８は入り口および出口管を分析管に深く挿入した状態を示す組み立てられた検出流セルを示す。
図９は無線周波（ＲＦ）シールドを備えた，組み立てられた検出流セルを示す。
実施例の説明
本発明の実施例の以下の説明は，以下の説明書きのある場合における（i）装置の特徴（ii）方法の動作を挙げて行われている。説明は基礎となる出願のクレームに基づくが，もちろんそのクレームは説明される実施例に限定されるものではない。カッコが付された符号は以下の注釈に対応し，カッコのない符号は図面中の符号に対応する。
ＮＭＲ流セル
本発明にしたがったＮＭＲ検出セル105[1]は：
（a）ＮＭＲ両立材料[3]から成り，入り口端部および出口端部を有し，さらに内径[4]を有する分析管220[2]と；
（b）ＮＭＲ両立材料[5]から成り，入り口端部[6]および出口端部を有し，さらに分析管[7]の内径より小さな内径を有する入り口管210と；
（c）ＮＭＲ両立材料から成り，入り口端部および出口端部を有し，さらに分析管の内径より小さな内径を有する出口管215と，から成り；
（d）入り口管[8]の出口端部は，円錐状にテーパーが付けられたノズル[9]を有し，分析管[10]の入り口端部の内側に配置され；
（e）出口管の入り口端部は円錐状にテーパーが付けられたノズルを有し，分析管の出口端部の内側に配置され；
（f）入り口管は分析管[11]に，入り口管[12]の出口端部から距離をおいてシールされており，このシール部が液体クロマトグラフィの流れに対して不活性であり；
（g）出口管は分析管に，出口管[12]の入り口端部から距離をおいてシールされされており，このシール部が液体クロマトグラフィの流れに対して不活性でありる。
製造方法
本発明にしたがってＮＭＲ流れセルを製造する方法は：
（a）ＮＭＲ両立材料から成り，入り口端部および出口端部を有し，さらに内径[13]を有する分析管を用意すること；
（b）ＮＭＲ両立材料から成り，入り口端部および出口端部を有し，分析管の内径より小さな内径を有し，さらに円錐状にテーパーが付けられたノズルを有する入り口管を用意すること；
（c）ＮＭＲ両立材料から成り，入り口端部および出口端部を有し，分析管の内径より小さな内径を有し，さらに円錐状にテーパーが付けられたノズルを有する出口管を用意すること；
（d）入り口管の出口端部を分析管[14]の入り口端部内に挿入すること；
（e）出口管の入り口端部を分析管の出口端部内に挿入すること；
（f）入り口管を分析管に，入り口管[15]の出口端部から距離をおいてシールすることであって，このシール部が液体クロマトグラフィの流れに対して不活性であるようにシールすること；
（g）出口管を分析管に，出口管の入り口端部から距離をおいてシールすることであって，このシール部が液体クロマトグラフィの流れに対して不活性であるようにシールすること；
から成る。
結合されたＨＰＬＣおよびＮＭＲ分光測定のための装置
本発明にしたがった，結合されたＨＰＬＣおよびＮＭＲ分光測定のための装置は：
（a）有機混合物を分離するための液体クロマトグラフ（ＬＣ）と；
（b）ＮＭＲ検出セルを有する核磁気共鳴（ＮＭＲ）と；から成り，
（c）ＮＭＲ検出セルは；
（i）ＮＭＲ両立材料から成り，入り口端部および出口端部を有し，さらに内径を有する分析管と；
（ii）ＮＭＲ両立材料から成り，入り口端部および出口端部を有し，さらに分析管の内径より小さな内径を有する入り口管と；
（iii）ＮＭＲ両立材料から成り，入り口端部および出口端部を有し，さらに分析管の内径より小さな内径を有する出口管と，から成り；
（iv）入り口管の出口端部は，円錐状にテーパーが付けられたノズルを有し，分析管の入り口端部の内側に配置され；
（v）出口管の入り口端部は，円錐状にテーパーが付けられたノズルを有し，分析管の出口端部の内側に配置され；
（vi）入り口管は分析管に，入り口管の出口端部から距離をおいてシールされされており，このシール部が液体クロマトグラフィの流れに対して不活性であり；
（vii）出口管は分析管に，出口管の入り口端部から距離をおいてシールされされており，このシール部が液体クロマトグラフィの流れに対して不活性であり；
（d）ＮＭＲ検出セルの入り口管の入り口端部は有機混合物の成分を受け入れるためにＬＣ内に組み込まれ，
（e）ＮＭＲ検出セルの出口管の出口端部は他の装置に組み込まれる。
注解
［１］検出セルは（必要というわけではないが）流れ用のセルである。他の実施例では，セルは入り口部分ですべて流れ込み，分析され，引き出されるサンプルの，停止した流れの下での分析用として使用でき，サンプルオートメーションの分野の当業者において周知の圧力制御器として使用される出口部分を有する。
さらに，セルは液体クロマトグラフィーの応用に限定されない。構造の強さおよび対称性は，一般的に流れのあるＮＭＲサンプルの導入に適用できる。小さいもの，大きいもの，小さいものとなる幾何学的特徴は，分析管を満たすために必要なサンプル（分析物および溶媒）の量を減少させ，全サンプル容積の増加した部分を分析管内に配置する。この特徴は，液体クロマトグラフィの分別が一例である限定された量しかないサンプルに対して有効である。
［２］分析管は適切な厚さから成るべきである。当業者にとって周知のように，管は薄ければ薄いほど組立，使用中に容易に破損し，厚ければ厚いほどＮＭＲ感度を低下させる。
［３］分析管は当業者には周知の，高純度の石英のようなＮＭＲ両立性材料から成る。ＰＹＲＥＸ（商標）のようなホウケイ酸ガラス組成物またはサファイアといった，十分にシールができる他のＮＭＲ両立性材料も使用できる。典型的な液体クロマトグラフィ（ＬＣ）およびＮＭＲ溶媒混合物の磁化率のいずれかと，実質的にゼロの磁化率と，空気と，または当該応用例に適したと思われる他のバランス対象とバランスがとれた磁化率をもつ材料も使用できる。
［４］当業者にはよく分かるように，分析管の内径は，使用されるＮＭＲ磁石の最善の磁場の長さおよび全体の分析容積がＬＣ応用例と両立するように選択される。たとえば，［AlbBay 88］を参照。ＮＭＲの穴の感度容積または磁場の中心の長さに基づいて分析管の長さを選択することはしばしば好適である。このとき，内径（i.d.）は，ＬＣの完全性（これは小容積の分析容積において第一義的な要件であり得る）がＮＭＲ（これは大容積の分析容積において第一義的な要件であり得る）により均衡がとられる。
［５］同じＮＭＲ両立材料が，分析管220，入り口管210，および出口管215に対して使用される。これに代わって，良好なシールが達成できる種々の材料が使用でき，分析管に対してよりも入り口管および出口管に対して，高価でないグレードの材料も使用できる。
［６］もし望むならば，入り口管の入り口端部（または出口管の出口端部，または両方）は，削られ，食刻され，機械削りされ，または刻み，溝をもつように形成され，または取付け接着剤のない在来の圧力留め具を使用して，改良されたコネクタ用にパターンを付けてもよい。このことは，取付け接着剤が液体クロマトグラフィの流れにおいて反応したり，溶融することから，不活性な方法でシールを形成することが望ましいので，利点となる。
［７］従来から知られているように，入り口管から分析管，そして出口管の直径が小さいもの，大きいものそして小さいものと進んでいくことは，流管がクロマトグラフ分析に使用されるとき，クロマトグラフ分離を維持するのに役立つ。
［８］図２の実施例において，組み立てられた流れセルが実質的に一様な外径をもつように入り口管および出口管の外径には段が付けられている。図４乃至７に示された他の実施例において，入り口管，出口管，または両方の外径は，分析管の外径より小さく，または大きくなってもよい。より小さい直径の壁厚が検出セルの全長にわたって維持されるときは，それはＨＰＬＣにおける使用に全く適さない。入り口管の入り口端部および出口管の出口端部における狭い壁は標準的なＨＰＬＣコネクタとともに使用するとき，破損に対して敏感となろう。分析管の外径に等しいか，または小さい外径をもつ入り口管および出口管を使用することにより最善の結果を得ると信じられている。或る適用例において，入り口管，出口管，またはその両方の外径が分析管の外径より大きいときは，困難性が生じる。
［９］テーパーが付けられたノズルは，分析管へ有効に流れ込み，そこから有効に出ていく（すなわち，流出する）ことを促進すると考えられている。円錐状のテーパーの使用は満足のいくものであり，テーパーの他の形態（たとえば，在来の長円をしたテーパー）も好適と信じられている。流れ方向に関して出口管のノズルは内向きにテーパーが付けられ，入り口管のノズルは外向きにテーパーが付けられている。
［10］入り口管の出口端部および出口管の入り口端部は，分析管の残りの容積が，ＮＭＲおよびクロマトグラフィ応用例の両方に対して適切となるように，分析管内で十分離されて配置されるべきである。特定の器具に対して，適切な残りの容積，および入り口管および出口管の端部がどれほど分析管に挿入されるべきかを決定することは，当業者により容易に行うことができる。
［11］シーリング：入り口管および出口管は，接着剤とともにまたは接着剤なしで，（たとえば，石英に対して）熱シーリング，（たとえば，サファイアに対して）ろうづけに，または他の適切な技術により分析管にシールされ得る。この開示内容を知る当業者にとって，シールを行うときには挿入可能なプラグの設計が対称なシールを容易にすることは分かるであろう。
［12］実質的な距離：分析管と入り口および出口管との間のシールは入り口管および出口管の，挿入された端部から十分に離れるべきで，その結果シールにより生じる磁場の乱れはＮＭＲの磁石の穴の感度容積（注解４）において，磁場に過度に影響を与えない。図８に図示の実施例において，挿入端部からシール点までの距離，0.675インチは十分で満足するものである。
［13］分析管，入り口管，および出口管は適切なＮＭＲおよびＬＣ両立材料（注解３および５）により正確に機械削りされるべきものである。分析管は高レベルの仕上げおよび対称性をもって利用できるように機械削りされるべきであるが，入り口および出口管は高レベルの対称性をもって利用できるように機械削りされても，好適には仕上げの必要はない。一実施例において，機械削りは，傾斜や面取りのないように，すなわち直角な縁をもつように行われる。
［14］環状の間隙内に分析液体や汚染物が捉えられる機会を減らすべく，可能な限り環状間隙を最小にするために，入り口および出口管は正確に機械削りされて分析管に挿入される。
［15］分析管への入り口および出口管のシールは高度の対称性をもって利用できるように行われるべきである。ろうづけ材料が使用されるときは，その材料も，ＮＭＲ両立性（すなわち，実質的に非磁性）であり，かつ化学的に両立性（すなわち，化学的に不活性）である。注解11を参照。
［16］ＮＭＲ検出セルを他の検出器またはサンプルコネクタまたは適切なチェーンに結合されることが望ましい。
付記
上述したＮＭＲは，それ自身の軸線225および流れセル230の長さに垂直な面により定義されるそれ自身の幾何学的な中心に関して非常に対称的となっている。使用において，セルは，対応して対称性をもつＮＭＲ磁石（これはＮＭＲ分解能および感度に顕著な改良をもたらす）に関して配置され得る。これらの特徴は，セルを，流れのあるもの用のＮＭＲプローブと一緒に使用するとき，さらに開発されたそのようなプローブと一緒に使用するとき非常に適切なものとする。
セルはまた高性能の液体クロマトグラフィ（ＨＰＬＣ）の使用が非常に適している。この理由の一つは，入り口および出口管の外端部の非常に厚い壁がＨＰＬＣコネクタとの使用に対して，容易にセルを順応させることができることである。セルは，液体クロマトグラフィを使用して有機混合物の成分を分離し，検出し，続いてＮＭＲにより成分の分光測定を行うために，結合したＨＰＬＣおよびＮＭＲスペクトロスコピー測定用の装置において使用することに，特に適している。
分析管の比較的薄い壁は，薄い壁が入り口および出口管内で使用されるとき生じる脆弱性（コネクタにより破損する）をともなわず，分析容積を増加させ，ＮＭＲ感度を向上させる。
セルの幾何学形状はＮＭＲコイルをセルに直接固定することを可能にし，その結果良好な充填率をもたらし，ＮＭＲ感度を改良し，少なくとも部分的に，ＮＭＲプローブ内でセルが回転しなことに関連した感度の低下を回避する。
セルは容易に量産でき，過度の困難性をともなわずにＮＭＲプローブ内に入れることができる。セルを内蔵するＮＭＲプローブはサンプルの寄生励起を減少または除去するためにＲＦシールドとともに使用でき，ＮＭＲ磁石の穴の感度領域の範囲を定める。このようなシールドの使用は従前のものであり，ここで権利化を図る検出セルの一部を構成するものではない。たとえば，ＲＦシールド910はＮＭＲ活性容積920を限定するために上記検出セルとともに使用でき，これにより三片のセルに関連するＮＭＲ分解能または感度への有害な効果が最小または除去される。入り口管から分析管に入り，または分析管を出て出口管へ入るサンプルはその内径が変化するために縦方向に対して不連続性を示す。ＲＦシールドは不連性により生じるＮＭＲ信号への影響を最小にするために設けられる。示されたようにＲＦシールドが設けられると，分析管の内側の直径と，入り口および出口管の内側の直径との間の環状領域でのＮＭＲピックアップは除去され得る。これら環状領域でのガラスのより大きな全直径による信号の減少，ノイズの増加もまた除去される。
文献目録
以下の文献目録は，当業者ならば知っているであろう背景技術を説明する参考文献として挙げられている。特にことわりのないものを除いて，これら文献はここの文献として組み入れられず，これら内容は請求の範囲の限定するものではない。
［AlbBay 88］Klaus AlbertおよびErnest Bayer，“高性能液体クロマトグラフィ-核磁気共鳴オンライン結合”，Analytical Chemistry，vol.7，No.8，1988，288-93［Lau Wil］David A.LaudeおよびCharles L.Wilkins，“液体クロマトグラフィの溶離液のオンライン識別のための核磁気共鳴検出”，Analytical Chemistry，vol.5，No.9，1986，230-35
この開示内容を理解する当業者であれば，上記説明した実施例が，本発明の範囲および思想から逸脱することなく種々の変形をなし得ることは分かるであろう。したがって，特許としての排他権の範囲は以下の請求の範囲に記載されている通りである。BACKGROUND OF THE INVENTION The present invention relates generally to the field of chemical analysis, in particular to the fields of high performance liquid chromatography (HPLC) and nuclear magnetic resonance spectroscopy (NMR), and in particular the on-line combination of the two analytical techniques. On how to enable. In particular, the present invention relates to an NMR detection cell that enables high-resolution, high-sensitivity and easy use of NMR with minimal adverse effects on HPLC resolution.
High performance liquid chromatography (HPLC) is widely used to separate organic mixtures. UV, refractive index and fluorescence detectors commonly used with HPLC are not as powerful as NMR for qualitative analysis of HPLC eluents, and infrared (IR) and mass spectrometers (MS) . Infrared and mass spectroscopy works well with gas chromatography (GC) for both separation and powerful spectroscopic analysis, but attempts to make a similar bond to HPLC for one of the preferred spectroscopic techniques work well There wasn't.
After extensive development, mass spectroscopy coupled with HPLC is commercially available. HPCL online binding to UV spectroscopy did not work due to solvent interference. NMR (which gives unmatched structural information and with sample conditions that are reasonably matched by HPLC) appears to be a suitable spectroscopic method coupled with HPLC.
Attempts to combine these two analytical techniques have basically failed due to the low sensitivity of the NMR detector. Since the advent of the first on-line coupled HPLC-NMR instrument in 1978 (LauWil86), improved NMR sensitivity has been achieved through the use of superconducting solenoidal NMR magnets rather than iron magnets. Another means for increasing the sensitivity of NMR is by the use of preliminary or semi-preliminary scale columns or analytical scale columns that are overfilled with excessive injection volumes.
These two alternatives have various drawbacks. The higher injection volume associated with any of these methods results in excessive band broadening. Band broadening further increases when a large dead space is required after the column to satisfy the pre-magnetization condition of the sample. Further disadvantages of these two methods include the rapid decline in column efficiency and the generation of large amounts of solvent that must be disposed of properly.
A better approach is to improve NMR sensitivity and limit volume injection to very small amounts. The present invention described herein provides a method for improving NMR sensitivity and line shape, while maintaining a low level of chromatographic band broadening and a high level of magnetic field uniformity.
SUMMARY OF THE INVENTION In accordance with one aspect of the present invention, a detection cell for a liquid chromatography sample is used in a nuclear magnetic resonance spectrometer. The detection cell includes an inlet tube having a conically tapered outlet nozzle, an analysis tube, and an outlet tube having a conically tapered inlet nozzle. The three tubes are composed of the same NMR compatible material (preferably any of high purity quartz, borosilicate glass composition and sapphire). The inner diameter of the analysis tube is larger than the inner diameter of the inlet tube and the outlet tube, so that the analysis tube has the form of small, large, and small.
The outlet end of the inlet tube is inserted into the inlet end of the analysis tube, and the inlet end of the outlet tube is inserted into the outlet end of the analysis tube. The inlet and outlet tubes are sealed to the analytical tube away from the inserted end in an appropriate manner.
The invention features (1) enable high mechanical strength in the small dimensions required for proper pressure-tolerant coupling from the HPLC system to the NMR, and (2) minimize the impact on the fluid output of the liquid chromatograph. And combining three tubes with different inner (straight) diameters in a way that allows an insertion seal while maintaining the high degree of structural symmetry required for NMR sensitivity and resolution.
The higher sensitivity of the NMR detector is obtained by increasing the signal to noise (S / N) ratio. Increasing the inner diameter of the analysis tube relative to the inlet and outlet tubes increases the signal volume due to the increased observation volume and reduces the glass diameter and noise, thereby achieving this. The observation volume does not increase to the point that it entails an increase in injection volume that would cause excessive band broadening.
The main advantage of a large analytical tube volume is that the signal intensity increases as the number of molecules increases in the detector with respect to the concentration of the sample. This allows for smaller diameter coils that result in noise reduction, depending on the overall design.
The described detector cell can be used for analysis under continuous flow or under stopped flow.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an NMR detection cell in a continuous flow cell 100.
FIG. 2 shows the assembled detection flow cell described herein.
FIG. 3 shows three individual pieces of the detection flow cell before being assembled.
Figures 4-7 show the various detection flow cells described.
FIG. 8 shows the assembled detection flow cell showing the inlet and outlet tubes inserted deep into the analysis tube.
FIG. 9 shows an assembled detection flow cell with a radio frequency (RF) shield.
Description of Embodiments The following description of the embodiments of the present invention is given by citing (i) the features of the apparatus (ii) the operation of the method in the case where the following description is given. The description is based on the claims of the underlying application, but of course the claims are not limited to the described embodiment. Symbols with parentheses correspond to the following annotations, and symbols without parentheses correspond to the symbols in the drawing.
NMR flow cell The NMR detection cell 105 [1] according to the invention is:
(A) an analytical tube 220 [2] comprising an NMR compatible material [3], having an inlet end and an outlet end, and further having an inner diameter [4];
(B) an inlet tube 210 made of an NMR compatible material [5], having an inlet end [6] and an outlet end, and having an inner diameter smaller than the inner diameter of the analytical tube [7];
(C) an NMR compatible material, having an inlet end and an outlet end, and further having an outlet tube 215 having an inner diameter smaller than the inner diameter of the analytical tube;
(D) The outlet end of the inlet tube [8] has a conically tapered nozzle [9] and is located inside the inlet end of the analytical tube [10];
(E) the inlet end of the outlet tube has a conically tapered nozzle and is located inside the outlet end of the analytical tube;
(F) The inlet tube is sealed to the analytical tube [11] at a distance from the outlet end of the inlet tube [12], which is inert to the liquid chromatography flow;
(G) The outlet tube is sealed to the analysis tube at a distance from the inlet end of the outlet tube [12], and this seal is inert to the liquid chromatography flow.
Manufacturing Method A method for manufacturing an NMR flow cell according to the present invention is:
(A) providing an analytical tube made of an NMR compatible material, having an inlet end and an outlet end, and further having an inner diameter [13];
(B) providing an inlet tube comprising an NMR compatible material, having an inlet end and an outlet end, having an inner diameter smaller than the inner diameter of the analytical tube, and having a conically tapered nozzle;
(C) providing an outlet tube comprising an NMR compatible material, having an inlet end and an outlet end, having an inner diameter smaller than the inner diameter of the analytical tube, and further having a conically tapered nozzle;
(D) inserting the outlet end of the inlet tube into the inlet end of the analytical tube [14];
(E) inserting the inlet end of the outlet tube into the outlet end of the analytical tube;
(F) sealing the inlet tube to the analytical tube at a distance from the outlet end of the inlet tube [15], so that this seal is inert to the liquid chromatography flow. thing;
(G) sealing the outlet tube to the analytical tube at a distance from the inlet end of the outlet tube, so that the seal is inert to the liquid chromatography flow;
Consists of.
Apparatus for combined HPLC and NMR spectroscopy In accordance with the present invention, an apparatus for combined HPLC and NMR spectroscopy is:
(A) a liquid chromatograph (LC) for separating the organic mixture;
(B) nuclear magnetic resonance (NMR) with an NMR detection cell;
(C) NMR detection cell;
(I) an analysis tube made of an NMR compatible material, having an inlet end and an outlet end, and further having an inner diameter;
(Ii) an inlet tube made of an NMR compatible material, having an inlet end and an outlet end, and having an inner diameter smaller than the inner diameter of the analytical tube;
(Iii) comprising an NMR compatible material, having an inlet end and an outlet end, and an outlet tube having an inner diameter smaller than the inner diameter of the analysis tube;
(Iv) The outlet end of the inlet tube has a conically tapered nozzle and is located inside the inlet end of the analytical tube;
(V) The inlet end of the outlet tube has a conically tapered nozzle and is located inside the outlet end of the analytical tube;
(Vi) the inlet tube is sealed to the analytical tube at a distance from the outlet end of the inlet tube, the seal being inert to the liquid chromatography flow;
(Vii) the outlet tube is sealed to the analytical tube at a distance from the inlet end of the outlet tube, the seal being inert to the liquid chromatography flow;
(D) The inlet end of the NMR detector cell inlet tube is incorporated into the LC to accept the components of the organic mixture,
(E) The exit end of the exit tube of the NMR detection cell is incorporated into another device.
Note [1] The detection cell is a cell for flow (although not necessary). In other embodiments, the cell can be used for analysis under a stopped flow of samples that are all flowed, analyzed and drawn at the inlet and used as a pressure controller well known to those skilled in the art of sample automation. Having an outlet portion.
Furthermore, the cell is not limited to liquid chromatography applications. Structural strength and symmetry are generally applicable to the introduction of flowing NMR samples. Small, large, and small geometric features reduce the amount of sample (analyte and solvent) needed to fill the tube and place an increased portion of the total sample volume in the tube . This feature is useful for samples with only a limited amount, for example liquid chromatography fractionation.
[2] The analytical tube should be of an appropriate thickness. As is well known to those skilled in the art, the thinner the tube, the easier it will break during assembly and use, the thicker the tube, the lower the NMR sensitivity.
[3] The analytical tube is made of an NMR compatible material, such as high purity quartz, well known to those skilled in the art. Other NMR compatible materials that can seal well, such as borosilicate glass compositions such as PYREX ™ or sapphire can also be used. Magnetization balanced with any of the typical liquid chromatography (LC) and NMR solvent mixture magnetic susceptibility, substantially zero magnetic susceptibility, air, or other balanced objects that may be suitable for the application. Materials with rates can also be used.
[4] As will be appreciated by those skilled in the art, the inner diameter of the analysis tube is selected such that the best magnetic field length and overall analysis volume of the NMR magnet used is compatible with the LC application. For example, see [AlbBay 88]. It is often preferred to select the length of the analysis tube based on the sensitivity volume of the NMR hole or the length of the center of the magnetic field. In this case, the inner diameter (id) is the LC integrity (which may be a primary requirement for small analysis volumes) but NMR (this is a primary requirement for large analysis volumes). Is possible).
[5] The same NMR compatible material is used for the analysis tube 220, the inlet tube 210, and the outlet tube 215. Alternatively, various materials that can achieve a good seal can be used , and less expensive grade materials can be used for the inlet and outlet tubes than for the analytical tubes .
[6] If desired, the inlet end of the inlet pipe (or the outlet end of the outlet pipe, or both) is cut, etched, machined, or chopped, formed with a groove, Alternatively, conventional pressure fasteners without mounting adhesive may be used to provide a pattern for the improved connector. This is an advantage because it is desirable to form the seal in an inert manner because the mounting adhesive reacts or melts in the liquid chromatography flow.
[7] As is known in the art, when the flow tube is used for chromatographic analysis, the diameter from the inlet tube to the analytical tube and the diameter of the outlet tube is small, large and small. Helps maintain chromatographic separation.
[8] In the embodiment of FIG. 2, the outer diameters of the inlet and outlet tubes are stepped so that the assembled flow cell has a substantially uniform outer diameter. In other embodiments shown in FIGS. 4-7, the outer diameter of the inlet tube, the outlet tube, or both may be smaller or larger than the outer diameter of the analytical tube. When a smaller diameter wall thickness is maintained over the entire length of the detection cell, it is totally unsuitable for use in HPLC. Narrow walls at the inlet end of the inlet tube and the outlet end of the outlet tube will be sensitive to breakage when used with standard HPLC connectors. It is believed that the best results are obtained by using inlet and outlet tubes with an outer diameter equal to or smaller than the outer diameter of the analysis tube. In some applications, difficulties arise when the outer diameter of the inlet tube, the outlet tube, or both are larger than the outer diameter of the analytical tube.
[9] It is believed that the tapered nozzle facilitates effective flow into and out of (ie out of) the analysis tube. The use of a conical taper is satisfactory and other forms of taper (eg, a conventional oval taper) are believed to be suitable. The nozzle of the outlet pipe is tapered inward with respect to the flow direction, and the nozzle of the inlet pipe is tapered outward.
[10] The outlet end of the inlet tube and the inlet end of the outlet tube are placed well separated in the analytical tube so that the remaining volume of the analytical tube is appropriate for both NMR and chromatographic applications. It should be. Determining the appropriate remaining volume and how much the end of the inlet and outlet tubes should be inserted into the analysis tube for a particular instrument can be readily performed by those skilled in the art.
[11] Sealing: Inlet and outlet tubes can be bonded with or without adhesive, heat sealing (for example against quartz), brazing (for example against sapphire) or other suitable technique Can be sealed to the analysis tube. Those skilled in the art who are aware of this disclosure will appreciate that the design of the insertable plug facilitates a symmetric seal when sealing.
[12] Substantial distance: The seal between the analysis tube and the inlet and outlet tubes should be well away from the inserted ends of the inlet and outlet tubes, so that the magnetic field disturbances caused by the seal are NMR In the sensitivity volume of the magnet hole (Note 4), the magnetic field is not excessively affected. In the embodiment shown in FIG. 8, the distance from the insertion end to the seal point, 0.675 inches, is sufficient and satisfactory.
[13] Analytical tubes, inlet tubes, and outlet tubes should be precisely machined with appropriate NMR and LC compatible materials (Notes 3 and 5). Analytical tubes should be machined so that they can be used with a high level of finish and symmetry, but the inlet and outlet tubes should preferably be machined so that they can be used with a high level of symmetry. There is no need. In one embodiment, the machining is performed without tilting or chamfering, that is, with a right edge.
[14] The inlet and outlet tubes are precisely machined and inserted into the analysis tube to minimize the annular gap as much as possible to reduce the chance of analysis liquid and contaminants trapped in the annular gap .
[15] The inlet and outlet tube seals to the analysis tube should be made available with a high degree of symmetry. When brazed materials are used, the materials are also NMR compatible (ie, substantially non-magnetic) and chemically compatible (ie, chemically inert). See Note 11.
[16] It is desirable to couple the NMR detection cell to another detector or sample connector or appropriate chain.
Note The NMR described above is highly symmetric with respect to its own geometric center defined by its own axis 225 and a plane perpendicular to the length of the flow cell 230. In use, the cell can be arranged with respect to a correspondingly symmetric NMR magnet, which provides a significant improvement in NMR resolution and sensitivity. These features make the cell very suitable when used in conjunction with NMR probes for those with flow and when used with such probes that have been further developed.
The cell is also very suitable for use with high performance liquid chromatography (HPLC). One reason for this is that the very thick walls at the outer ends of the inlet and outlet tubes can easily accommodate the cell for use with HPLC connectors. The cell is intended to be used in a combined HPLC and NMR spectroscopy instrument to separate and detect components of an organic mixture using liquid chromatography, followed by spectroscopic measurement of the components by NMR. Especially suitable.
The relatively thin walls of the analysis tube increase the analysis volume and improve the NMR sensitivity, without the fragility that occurs when the thin walls are used in the inlet and outlet tubes (damaged by the connector).
The cell geometry allows the NMR coil to be fixed directly to the cell, resulting in a good fill factor, improved NMR sensitivity, and at least partially without rotating the cell within the NMR probe. Avoid associated sensitivity loss.
The cell can be easily mass-produced and placed in the NMR probe without undue difficulty. An NMR probe incorporating the cell can be used with an RF shield to reduce or eliminate parasitic excitation of the sample and delimits the sensitivity region of the hole in the NMR magnet. The use of such a shield is conventional and does not constitute part of the detection cell to be licensed here. For example, the RF shield 910 can be used with the detection cell to limit the NMR active volume 920, thereby minimizing or eliminating the detrimental effect on NMR resolution or sensitivity associated with the three-piece cell. Samples that enter the analysis tube from the inlet tube or leave the analysis tube and enter the outlet tube exhibit discontinuities in the longitudinal direction due to changes in their inner diameter. The RF shield is provided to minimize the effect on the NMR signal caused by discontinuities. If an RF shield is provided as shown, the NMR pickup in the annular region between the inner diameter of the analysis tube and the inner diameter of the inlet and outlet tubes can be removed. The reduction in signal and increase in noise due to the larger total diameter of the glass in these annular regions are also eliminated.
Bibliography The following bibliography is listed as a reference describing background art that would be known to those skilled in the art. Except as otherwise noted, these references are not incorporated herein and their contents are not intended to limit the scope of the claims.
[AlbBay 88] Klaus Albert and Ernest Bayer, “High Performance Liquid Chromatography-Nuclear Magnetic Resonance Online Coupling”, Analytical Chemistry, vol. 7, No. 8, 1988, 288-93 [Lau Wil] David A. Laude and Charles L Wilkins, “Nuclear Magnetic Resonance Detection for Online Identification of Eluents in Liquid Chromatography,” Analytical Chemistry, vol. 5, No. 9, 1986, 230-35
Those skilled in the art who understand this disclosure will appreciate that the embodiments described above can be variously modified without departing from the scope and spirit of the invention. Therefore, the scope of patent exclusive rights is as described in the following claims.

Claims

An NMR detection cell for a liquid chromatography sample ,
(A) an analysis tube having an inlet end and an outlet end and having an inner diameter;
(B) an inlet tube having an inlet end and an outlet end and having an inner diameter smaller than the inner diameter of the analytical tube;
(C) an outlet tube having an inlet end and an outlet end and having an inner diameter smaller than the inner diameter of the analytical tube;
(D) the outlet end of the inlet tube has a conically tapered nozzle and is located inside the inlet end of the analytical tube;
(E) the inlet end of the outlet tube has a conically tapered nozzle and is located inside the outlet end of the analytical tube;
(F) The inlet tube is sealed to the analysis tube at a distance from the outlet end of the inlet tube, and the distance is selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this sealed portion. , This seal is inert to the liquid chromatography flow;
(G) The outlet tube is sealed to the analysis tube at a distance from the inlet end of the outlet tube, and the distance is selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this sealing portion. , Ri inert der the seal portion to the flow of liquid chromatography;
(H) A detection cell where the same material is used for the analysis tube, inlet tube and outlet tube .

An NMR detection cell for a liquid chromatography sample ,
(A) an analysis tube having an inlet end and an outlet end and having an inner diameter;
(B) an inlet tube having an inlet end and an outlet end and having an inner diameter smaller than the inner diameter of the analytical tube;
(C) an outlet tube having an inlet end and an outlet end and having an inner diameter smaller than the inner diameter of the analytical tube;
(D) the outlet end of the inlet tube has a tapered nozzle and is located inside the inlet end of the analytical tube;
(E) the inlet end of the outlet tube has a tapered nozzle and is located inside the outlet end of the analytical tube;
(F) The inlet tube is sealed to the analysis tube at a distance from the outlet end of the inlet tube, and the distance is selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this sealed portion. , This seal is inert to the liquid chromatography flow;
(G) The outlet tube is sealed to the analysis tube at a distance from the inlet end of the outlet tube, and the distance is selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this sealing portion. , Ri inert der the seal portion to the flow of liquid chromatography;
(H) An NMR detection cell where the same material is used for the analysis tube, the inlet tube, and the outlet tube .

The NMR detection cell according to claim 2, wherein the inner diameter of the inlet tube is equal to the inner diameter of the outlet tube.

3. An NMR detection cell according to claim 2, wherein the inlet tube has an outer diameter equal to the outer diameter of the analytical tube at the inlet end.

3. An NMR detection cell according to claim 2, wherein the outlet tube has an outer diameter equal to the outer diameter of the analytical tube at the outlet end.

3. The NMR detection cell according to claim 2, wherein the inlet tube has an outer diameter larger than the outer diameter of the analytical tube at the inlet end.

3. The NMR detection cell according to claim 2, wherein the inlet tube has an outer diameter smaller than the outer diameter of the analytical tube at the inlet end.

3. The NMR detection cell according to claim 2, wherein the outlet tube has an outer diameter larger than the outer diameter of the analytical tube at the outlet end.

3. The NMR detection cell according to claim 2, wherein the outlet tube has an outer diameter smaller than the outer diameter of the analysis tube at the outlet end.

3. The NMR detection cell according to claim 2, wherein the detection cell is used as a flow cell through which the detection cell flows.

3. The NMR detection cell according to claim 2, wherein the detection cell is used as a stationary flow cell.

The NMR detection cell according to claim 1, wherein the detection cell is used as a flow cell in which the detection cell is continuously flowing.

The NMR detection cell according to claim 1, wherein the detection cell is used in a stationary flow cell apparatus.

The method for producing an NMR detection cell for a liquid chromatography sample is:
(A) providing an analytical tube having an inlet end and an outlet end and having an inner diameter;
(B) inlet end and an outlet end, further have a smaller inner diameter than the inner diameter of the analysis tube, a inlet pipe of the same material being used and the analysis tube, the outlet end of the inlet tube is tapered Providing an inlet tube with a nozzle marked with ;
(C) the inlet end and an outlet end, further have a smaller inner diameter than the inner diameter of the analysis tube, a exit tube of the same material being used and the analysis tube, the inlet end of the outlet tube Providing an outlet tube having a tapered nozzle ;
(D) inserting the outlet end of the inlet tube into the inlet end of the analytical tube;
(E) inserting the inlet end of the outlet tube into the outlet end of the analytical tube;
(F) sealing the inlet tube to the analysis tube at a distance from the outlet end of the inlet tube, the distance being selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this seal. and which, that the seal portion is sealed so it is inert to the flow of liquid chromatography;
(G) sealing the outlet tube to the analytical tube at a distance from the inlet end of the outlet tube, the distance being selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this sealing portion. and which, that the seal portion is sealed so it is inert to the flow of liquid chromatography;
A manufacturing method comprising:

A method according to claim 1 4, inlet and an inner diameter smaller than the inner diameter of the analysis tube outlet tube, at the method.

An NMR detection cell for a liquid chromatography sample ,
(A) an analysis tube having an inlet end and an outlet end and having an inner diameter;
(B) an inlet tube having an inlet end and an outlet end and having an inner diameter;
(C) an outlet pipe having an inlet end and an outlet end and having an inner diameter;
(D) the outlet end of the inlet tube has a tapered nozzle and is located inside the inlet end of the analytical tube;
(E) the inlet end of the outlet tube has a tapered nozzle and is located inside the outlet end of the analytical tube;
(F) The inlet tube is sealed to the analysis tube at a distance from the outlet end of the inlet tube, and the distance is selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this sealed portion. , This seal is inert to the liquid chromatography flow;
(G) The outlet tube is sealed to the analysis tube at a distance from the inlet end of the outlet tube, and the distance is selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this sealing portion. , Ri inert der the seal portion to the flow of liquid chromatography;
(H) An NMR detection cell where the same material is used for the analysis tube, the inlet tube, and the outlet tube .

An NMR detection cell for a liquid chromatography sample ,
(A) an analysis tube having an inlet end and an outlet end and having an inner diameter;
(B) an inlet pipe having an inlet end and an outlet end and having an inner diameter;
(C) The outlet end of the inlet tube has a tapered nozzle and is located inside the inlet end of the analytical tube;
(D) The inlet tube is sealed to the analytical tube at a distance from the outlet end of the inlet tube, and the distance is selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this sealed portion. , Ri inert der the seal portion to the flow of liquid chromatography,
(E) An NMR detection cell where the same material is used for the analysis tube and the inlet tube .

The NMR detection cell according to claim 17 ,
(A) an outlet tube having an inlet end and an outlet end and further having an inner diameter, wherein the outlet tube is made of the same material as the analysis tube ;
(C) The inlet end of the outlet tube has a tapered nozzle and is located inside the outlet end of the analytical tube;
(D) The outlet tube is sealed to the analysis tube at a distance from the inlet end of the outlet tube, and the distance is selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this seal portion. the seal portion is inactive to the flow of liquid chromatography, at the NMR detection cell.

An instrument for combined HPLC and nuclear magnetic spectroscopy measurements, comprising:
(A) a liquid chromatograph (LC) for separating the organic mixture;
(B) a nuclear magnetic resonance (NMR) spectrometer having an NMR detection cell;
(C) NMR detection cell;
(I) an analysis tube having an inlet end and an outlet end and having an inner diameter;
(Ii) an inlet tube having an inlet end and an outlet end and having an inner diameter smaller than the inner diameter of the analytical tube;
(Iii) an outlet tube having an inlet end and an outlet end and having an inner diameter smaller than the inner diameter of the analytical tube;
(Iv) The outlet end of the inlet tube has a conically tapered nozzle and is located inside the inlet end of the analytical tube;
(V) The inlet end of the outlet tube has a conically tapered nozzle and is located inside the outlet end of the analytical tube;
(Vi) the inlet tube to the analysis tube, is sealed at a distance from the outlet end of the doorway tube, the distance is selected such that the sensitivity of NMR spectroscopy is not degraded due to the seal portion cage, the seal portion be inert with respect to the flow of liquid chromatography;
(Vii) The outlet tube is sealed to the analysis tube at a distance from the inlet end of the outlet tube, and the distance is selected so that the sensitivity of NMR spectroscopy does not deteriorate due to this sealing portion. , This seal is inert to the liquid chromatography flow;
(Viii) The same material is used for the analysis tube, inlet tube and outlet tube;
(D) the inlet end of the inlet tube of the NMR detection cell is Ru incorporated into the LC to receive the components of the organic mixture,
But the device.

20. The apparatus according to claim 19 , wherein the apparatus is used for a flow cell apparatus in which detection cells are continuously flowing.

21. The apparatus according to claim 20 , wherein the detection cell is used in a stationary flow cell apparatus.

A NMR detection cell according to any one of claims 1 to 1 3 and 1 6,
A seal portion between the inlet tube and the analysis tube is configured by any one of heat sealing, brazing, and using a pressure fastener;
An NMR detection cell in which a seal portion between the outlet tube and the analysis tube is constituted by one of heat sealing, brazing, and using a pressure fastener.

A method according to claim 1 4 or 1 5,
Sealing the inlet tube to the analysis tube includes any of heat sealing, brazing, and using a pressure fastener;
The method wherein sealing the outlet tube to the analysis tube includes any of heat sealing, brazing, and using a pressure fastener.

18. The NMR detection cell according to claim 17 , wherein the seal portion between the inlet tube and the analysis tube is configured by any one of heat sealing, brazing, and using a pressure fastener. , But NMR detection cell.

19. The NMR detection cell according to claim 18 , wherein a seal portion between the outlet tube and the analysis tube is configured by any one of heat sealing, brazing, and using a pressure fastener. , But NMR detection cell.

The apparatus according to any one of claims 19 to 21 , comprising:
A seal portion between the inlet tube and the analysis tube is configured by any one of heat sealing, brazing, and using a pressure fastener;
Seal portion between the analysis tube and the outlet tube, heat sealing, Brazed, and is constituted either by the use of pressure fasteners, at the device.

A NMR detection cell according to any one of claims 1,1 2 and 1 3, wherein the analysis tube, the inlet tube and the outlet tube, high purity quartz, or borosilicate glass compositions and sapphire An NMR detection cell consisting of

A method according to claim 1 4, wherein the analysis tube, the inlet tube and the outlet tube, consists of either a high-purity quartz, borosilicate glass compositions and sapphire, where methods.

17. The NMR detection cell according to claim 16 , wherein the analysis tube, the inlet tube, and the outlet tube are made of any one of high-purity quartz, a borosilicate glass composition, and sapphire.

18. The NMR detection cell according to claim 17 , wherein the analysis tube and the inlet tube are made of any one of high-purity quartz, a borosilicate glass composition, and sapphire.

19. The NMR detection cell according to claim 18 , wherein the outlet tube is made of any one of high-purity quartz, a borosilicate glass composition, and sapphire.

20. The apparatus according to claim 19 , wherein the analysis tube, the inlet tube, and the outlet tube are made of any one of high-purity quartz, a borosilicate glass composition, and sapphire.